Digital Antianxiety Treatment and Cognitive Performance: an Experimental Study
Last registered on December 18, 2019


Trial Information
General Information
Digital Antianxiety Treatment and Cognitive Performance: an Experimental Study
Initial registration date
December 10, 2019
Last updated
December 18, 2019 10:57 AM EST
Primary Investigator
King's Business School, King's College London
Other Primary Investigator(s)
PI Affiliation
Swiss Tropical and Public Health Institute
PI Affiliation
Department of Political Economy, King's College London
Additional Trial Information
Start date
End date
Secondary IDs
We study the impact of an innovative antianxiety digital treatment on performance in a cognitive demanding task using a randomized control trial design. We exogenously manipulate a cognitive bias associated with anxiety – the tendency to disproportionately
allocate attention to negative stimuli – in a group of young men and women using a digital treatment called Cognitive Bias Modification. CBM treatment reduces attention bias by training individual attention. It is a computer-based training in which pairs of threatening and neutral visual stimuli appear sequentially on the screen. The subject is trained to divert attention away from threatening stimuli by requiring repeated identification of the location of the neutral stimulus in a pair of neutral and threatening stimuli. We observe that the treatment reduces the cognitive bias of treated women and significantly improves their performance in the cognitive task.
External Link(s)
Registration Citation
Cavatorta, Elisa, Simona Grassi and Mark Lambiris. 2019. "Digital Antianxiety Treatment and Cognitive Performance: an Experimental Study." AEA RCT Registry. December 18.
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Experimental Details
CBM treatment aims to mitigate the attention bias (a cognitive bias associated to anxiety) that manifests with a disproportionate (subconscious) focus towards threatening stimuli. CBM training corrects the bias by re-diverting the focus towards neutral or positive stimuli. The treatment is computer-based and involves the rapid sequential appearance of pairs of visual stimuli on the screen. We adopted the version of CBM that uses pairs of photographs of human faces as visual stimuli. In each pair of photographs, the face of the
same person appears with an angry expression (threat stimulus) and an emotionally and an emotionally
neutral expression (neutral stimulus). Participants see each pair of angry and neutral faces at the center of their computer screen for 500 milliseconds (ms), before the faces disappear. The photographs are juxtaposed from left to right with a space in between. The location of the angry and the neutral faces on the right or on the left of the screen is randomized. After the faces have disappeared, a probe (in the form of a small cross) pops up for 500 ms at the location of one of the two images. The task for the participant is to identify the location of the probe as rapidly and accurately as possible by clicking on a prespecified key on the keyboard, one for the left and one for the right position. Then, another screen with another pair of faces appears and the procedure repeats. A CBM session consists of 360 consecutive
screens. A session lasts for about 10 minutes. The participants in our study completed a minimum of 16 sessions (one per day).
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Changes in: 1) Measures of attention bias 2) Performance in a cognitive task
Primary Outcomes (explanation)
1) Measures of attention bias: response time to identify a neutral stimulus versus a threat stimulus
2) Performance in a cognitive task: measured by the number of attempted questions and correct answers to a selection of questions from the Raven Progressive Matrices test completed within 10 minutes.
Secondary Outcomes
Secondary Outcomes (end points)
3) Confidence in the cognitive test result 4) Decision under uncertainty
Secondary Outcomes (explanation)
3) Confidence in the cognitive test result: measured by a price-list type task played in anonymous (random) pairs. Each decision consists in choosing between Option 1 - an uncertain gamble between a fixed payoff with increasing winning probability and a payoff of zero - and Option 2 - a gamble where the high payoff materialises only if the actual subject's performance in the cognitive task is higher than that of the randomly chosen partner.
4) Decision under uncertainty: four price-list type tasks. Tasks A and B are value equivalent tasks. Task A elicits the equivalence between a certain payoff and a gamble with fixed probability and varying payoffs. Task B elicits the lowest payoff in a gamble (x1, x2, q) that is considered indifferent to task's A gamble.
Experimental Design
Experimental Design
The experiment is based on a longitudinal design with randomization of the treatment at the individual level. Participants took part in a baseline laboratory session that included the first CBM intervention. Part of the CBM treatment was conducted at home, over a
period of three weeks, for a total of 14 CBM completed sessions at home. The experiment concluded with a follow-up laboratory session that included the last CBM session. We incentivized participation with a contribution of CHF 110 (approximately GBP 91) to be
paid at the end of the study on condition of full compliance.
Experimental Design Details
Randomization Method
In office by computer
Randomization Unit
individual level
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
300 not clustered
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
Total: 261 subjects completed the training.
Men: 67 in Treatment group and 63 in Control group
Women: 65 in Treatment and 66 in Control group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
Faculty of Business and Economics (HEC Lausanne)
IRB Approval Date
IRB Approval Number
N/A, approved under acronym "LAGRA"
Post Trial Information
Study Withdrawal
Is the intervention completed?
Intervention Completion Date
November 21, 2014, 12:00 AM +00:00
Is data collection complete?
Data Collection Completion Date
November 21, 2014, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Final Sample Size (or Number of Clusters) by Treatment Arms
Treated: 132 Control: 129
Data Publication
Data Publication
Is public data available?

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Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers